The advent of soft contact lenses fabricated from pliable plastic materials has greatly increased the comfort and convenience associated with wearing contact lenses. Unlike the earlier "hard" contact lenses, however, soft contact lenses are generally quite hydrophilic and are thus susceptible to contamination by micro-organisms. Accordingly, soft contact lenses must be disinfected or sterilized daily if irritation or infection of the wearer's eyes is to be avoided.
Many of the contact lens sterilizing techniques heretofore developed rely upon the heating of the lenses to a high temperature in the presence of a saline solution, whereby destruction of the micro-organisms is achieved. Of course, before heat sterilized lenses can be safely reinserted in a wearer's eyes, the lenses must cool sufficiently. Numerous means have been devised, both in the contact lens sterilizing field per se and in analgous arts, for decreasing the amount of time necessary to complete this cooling step. U.S. Pat. No. 2,556,495, for instance, issued to Freedman on June 12, 1951, discloses a sterilizing apparatus wherein articles supported in a sterilizing tray are removed from the hot water of a sterilizing tank through the actuation of a link and lever mechanism and deposited in a receptacle containing cooling fluid. Despite the efforts by Freedman and others to reduce the inconvenience associated therewith, the use of heat to achieve sterilizing action requires relatively bulky and complicated equipment, thus rendering heat sterilization processes cumbersome with respect to small articles in general and contact lenses in particular.
Several contact lens sterilizing techniques overcome the disadvantages inherent in heat sterilizing systems by employing anti-microbial solutions in lieu of heat to carry out the sterilizing operation. U.S. Pat. No. 3,912,451, issued Oct. 14, 1975, describes such a technique for sterilizing contact lenses with hydrogen peroxide (H.sub.2 O.sub.2). Unfortunately, the use of anti-microbial solutions is not without its own drawbacks, inasmuch as many anti-microbial solutions are injurious to the eyes. Care must consequently be taken to insure that any sterilizing solution remaining on the contact lenses after chemical treatment has been completed is neutralized before the lenses are worn again. Examples of apparatus for controlling both the immersion of contact lenses in an anti-microbial solution of hydrogen peroxide and the neutralization of the solution following sterilization can be found in U.S. Pat. No. 4,013,410, issued to Thomas et al on Mar. 22, 1977 and U.S. Pat. No. 4,143,116, issued to Meltzer on Mar. 6, 1979. Thomas et al specifically discloses a timer actuated rotatable bracket which automatically flips a capsule containing contact lenses submerged in hydrogen peroxide from an upright position to an inverted position after a predetermined interval of time, whereupon the hydrogen peroxide flows into contact with a catalytic agent and is reduced to water. Meltzer also relies upon the inversion of a contact lens-carrying capsule to bring the lens sterilizing solution into contact with a neutralizing substance, but instead of the rotatable bracket of Thomas et al, Meltzer utilizes a cammed catch release arrangement to permit gravity assisted swinging of the capsule into the inverted position.
It can be seen that the aforementioned patents teach a practical means for chemically destroying potentially injurious micro-organisms on contact lenses. Nevertheless, the Meltzer and Thomas et al apparatus exhibit certain inherent limitations. Neither Meltzer nor Thomas et al actually remove the contact lenses from the hydrogen peroxide subsequent to the sterilizing process. Hence, the entire volume of hydrogen peroxide used in the Meltzer and Thomas et al apparatuses must be neutralized in order to render the contact lenses wearable. Neutralization of such a relatively large amount of hydrogen peroxide in turn consumes a disproportionate amount of time. Moreover, the hydrogen peroxide once neutralized provides a less than ideal storage environment for the lenses. As a net result, the prior art fails to disclose a truly simple, reliable, yet effective device for chemically sterilizing contact lenses in a relatively short period of time with a minimum of risk to the contact lens wearer.